1. Field of the Invention
This invention relates to a data imprinting device for a camera capable of underwater photography.
2. Description of the Prior Art
A majority of the recently developed cameras have the data imprinting device carried on the back cover. The data from an electronic timer circuit are displayed by liquid crystal light shutter display elements, and, when the display is illuminated from the back, are imprinted on the photographic film. To correct or select these data, or to set the film sensitivity, there are actuators which are usually in most cases constructed in the form of push button switches. When in application of this kind of data imprinting device to cameras capable of underwater photography, measures must be taken to prevent erroneous inputs from occurring when the water pressure becomes so high as to press the push buttons. According to the prior art, a water depth meter is incorporated in the camera and renders the push button switches unable to set or adjust the display when the water depth is deeper than a certain value, as disclosed in Japanese Laid-Open Patent Application No. SHO 58-173725. Once the input-locking is effected, all actuating operations are rejected. This can be known by the user only when he sees that the data readout in the display window is not responsive to the actuation of the buttons. Since under water at so deep a depth as to lock the input data, however, the available light is very low, it is difficult to make sure the input data are not locked. If the user is unaware of the fact that the input data have been locked, incorrect data will be imprinted in a continuous series of frames of the film.